In the dairy industry, milk is sold in a variety of containers, including paper-based cartons of various sizes. In order to reduce the cost of handling the individual cartons, they are customarily packed in crates for shipment to stores. Typically, the cartons are removed by the store employees and placed on shelves so that customers can remove individual packages from the shelves. The empty crates are then returned to the dairy or to the packaging plant to be filled again with cartons.
The crates are relatively light in weight, but occupy a large volume. As a result, the empty crates that are stored at the packaging facility require a large amount of space. Often the crates are stacked out-of-doors where they are subject to being blown over by wind or are maintained in very tall stacks which are difficult to handle.
Although machines are available for packing cartons in the crates, these machines operate relatively slowly. Since the crates are in the form of an open box with four rigid side walls, it is necessary for the machines to lower the cartons through the top of the crate, which may cause excessive stress on the packaging material that can lead to leakage of the cartons.
It has been proposed previously to utilize crates that have folding sides. U.S. Pat. No. 4,998,637 is an example of a crate having four folding sides which are held in an upright position by a band which encircles the side. Although this type of crate has the advantage of reducing the volume of the empty crate, but the crate is filled with cartons utilizing the conventional packing method of filling the crate through the open top.
Some of the inefficiencies of prior crate systems have been overcome by the method and apparatus disclosed in U.S. Pat. No. 5,020,304. This patent discloses the use of a folding crate which has only two side walls. The other two side walls are open. When cartons are placed between the two upright side walls, a strap is applied around the circumference of the crate to hold the cartons in the crate. This form of crate is also disclosed in U.S. patent application Ser. No. 07/535,341 filed Jun. 11, 1990, entitled "Folding Crate for Holding Packages".
Although the method and apparatus disclosed in U.S. Pat. No. No. 5,020,304 provide an efficient system for handling the filled cartons, it is nevertheless advantageous to improve the efficiency, cost and rate of production of the method and apparatus for handling and filling the crates.